Biomedical subjects

I V Efimova

Publications and source records attributed to I V Efimova.

At least 19 recordsLinked to original sources

PubMed1992

Ultrasonic vocalizations by rat pups: the primary importance of ambient temperature and the thermal significance of contact comfort.

We investigated the effects of isolation, huddling, and air temperature on ultrasound production by rat pups. Experiment 1 showed that ultrasound production by 8- to 9-day-olds was minimal at thermoneutrality and increased in response to small deviations of air temperature on either side of the thermoneutral zone. Experiments 2 and 3 showed that suppression of ultrasound production by contact with littermates is consistent with the thermal consequences of huddling. Experiment 4 showed that, contrary to previous conclusions, ultrasound production is not independent of ambient temperature in pups older than 10 days of age. Taken as a whole, these experiments emphasize (1) the importance of ambient temperature for the elicitation of ultrasound by rat pups of all ages studied, (2) the importance of thermal factors in the suppression of ultrasound by littermate contact, and (3) the manner in which different methods can change interpretations of the behavior and physiology of infant rats.

Animals↗

PubMed1992

Thermogenesis during ultrasonic vocalization by rat pups isolated in a warm environment: a thermographic analysis.

Ultrasonic vocalizations, emitted by rat pups when separated from their mother, littermates, and home cage, have been used as a measure of isolation distress. Recently, we demonstrated that cold exposure is the primary component of isolation that induces the vocalization. We were unable, however, to suppress all ultrasound production when transferring pups to a thermoneutral (35 degrees C) environment. Using an infrared thermography system that allows us to estimate noninvasively heat production by brown adipose tissue, we found that pups transferred from the home nest to a 35 degree C test chamber exhibited sizable levels of heat production while they were vocalizing. Moreover, both heat production and ultrasound emission decreased over the 15-min test. Next, we used extreme care to minimize thermal, and therefore respiratory, stimulation of pups before, during, and after the transfer procedure. We found that such precautions prevented both heat production and ultrasound emission following transfer. These results indicate that infant rats' thermal sensitivities are far greater than previously suspected.

Adipose Tissue, Brown↗

PubMed1990

[Phospholipids and glycosphingolipids in cultured skin fibroblasts from healthy donors and patients with systemic scleroderma].

A comparative study of phospho- and glycosphingolipids of cultured skin fibroblast from healthy donors and from patients with systemic sclerodermia (SSD) was carried out. It was shown that the total phospholipid content in SSD fibroblasts is elevated. No significant changes in the concentration of neutral glycosphingolipids were observed. The ganglioside composition of SSD cell cultures differs significantly from that of healthy donor cells. The concentration of the gangliosides, GM3 and GM1, is decreased; no ganglioside GD1a was found in SSD fibroblasts. The data obtained are suggestive of changes in the properties of fibroblast surface which can be manifested both in the impaired reception of matrix proteins and in the impairment of basic properties of the membrane. These changes are well correlated with the results of previous studies on the AMP cyclase system.

Adult↗

PubMed1982

[Inhibitory effect of combined administration of neuraminidase and interferon in mice with Rauscher leukemia].

A study was made of the effect of cholera vibrio neuraminidase and mouse interferon on the development of Rauscher's leukemia in BALB/c mice. It was shown that administration of 1500 units interferon to mice 4 hours before and 5 days after inoculation of Rauscher's leukemia virus prolonged the animals' lifespan. Preliminary treatment of the virus-containing material with neuraminidase prevented the death of one third of the experimental animals. Meanwhile the remainder of the animals inoculated with the same virus showed a longer lifespan. Combined use of both the preparations proved the most effective, enabling the prevention from death of 90% of the experimental animals. The mechanism of antiviral action of neuraminidase and interferon is discussed.

Animals↗

PubMed1982